DIY Build .450 Bushmaster Bolt Gun

[DrewFS]

Hey guys looking for insight...I’m planning out a .450 Bush with DBM build for southern Michigan deer hunting and I’m trying to determine which action to use. I have a 12 LRP that I rebuilt and love so was contemplating acquiring that action to build from. The question I have is, is the large shank a benefit or hindrance when it comes to the .450?

Should I just go with a 10 small shank?

[GaCop]

I built my Bushmaster on an Axis action. I've put some very hefty loads through it (425 grain WFN-GC, 1623 fps. 350 and 400 grain Speer JSP) without any problems. The Speer bullets were originally 45-70 bullets that I resized to .452". I have almost 800 rounds thorough the rifle to date. I used a Rhineland 16 inch barrel with 1/16" twist. The Rhineland is small shank of course. Biggest headache is getting rounds to feed through the DM. Hornady 250 grain FTXs feed the best. To use a large shank barrel you would have to have one custom made, all the Bushmaster barrels I've looked at are small shank.

[DrewFS]

GACop, what bottom metal did you go with? I was looking at Northland Shooter Supply and they have model 10 with AICS mag bottom metal included. I was hoping this would work as an alternative to the model 12 which NSS also has. I used CDI DBM on my 12LRP rebuild but CDI is sadly no longer and option. What feeding problems did you have and how did you solve them?


Shoot

[GaCop]

GACop, what bottom metal did you go with? I was looking at Northland Shooter Supply and they have model 10 with AICS mag bottom metal included. I was hoping this would work as an alternative to the model 12 which NSS also has. I used CDI DBM on my 12LRP rebuild but CDI is sadly no longer and option. What feeding problems did you have and how did you solve them?


Shoot

I'm using my original Axis DM that was 243 Win. and a factory Axis stock with varmint barrel channel. I modified the DM with a 1/2" spacer in the rear of the mag box and shortened the follower. I also reversed the follower spring. To date, only the 250 gr FTX, 350 grain Hornady and 400 grain Speer JSN (sized to .452"), along with the 245 grain Hornady JHPs feed reliably from the magazine. Blunt nose bullets still hang up. I can get only two Bushmaster rounds into the magazine and one chambered.

[DrewFS]

Yeah I really want to use AICS mags and as long as the capacity is 3 or so I'm good. I just want reliable feeding. I'm assuming it's possible since both Savage and Ruger are now offering .450 Bush bolt guns. The other question regarding shank size, I was just thinking the large shank has a longer tenon which would provide more support for the large diameter heavy barrel. I'm thinking a varmint weight 20-22" with 0.8" or so at the muzzle.

[GaCop]

Yeah I really want to use AICS mags and as long as the capacity is 3 or so I'm good. I just want reliable feeding. I'm assuming it's possible since both Savage and Ruger are now offering .450 Bush bolt guns. The other question regarding shank size, I was just thinking the large shank has a longer tenon which would provide more support for the large diameter heavy barrel. I'm thinking a varmint weight 20-22" with 0.8" or so at the muzzle.

IIRC, the large shank barrels only fit the Savage target actions and 338 Lapua action.

[mattri]

I too built off a small shank Axis action and had 0 problems. I was running an 18" varmint contour with no problems- you'll be fine with a small shank.

Also, I still have my 450BM GO gauge, you're welcome to borrow it when you get to that point.

[DrewFS]

Mattri, that's good info, thanks! And thank you for the go gauge offer!